Question

A coin is thrown 3 times .what is the probability that atleast one head is obtained?
O 718
9/8
O 3/4
None of the above​

Answer 1

none of the above

hope it's help you

Answer 2

The best possible answer would be if you write all the out comes of tossing of 3 times.

Let E1 be total no. of outcomes for 3 times tossing.

let E2 is the favourable outcomes of at least 1 head( i.e; 1head or 2 head or 3 head)

⇒ E1 =(HHH, HHT, HTH THH,TTT,TTH,THT,HTT)

nE1=8

⇒E2 = (HHH, HHT, HTH THH,TTH,THT,HTT)

nE2=7

thus, P(at least one head)= nE2/nE1

⇒ 7/8 Ans